Using STA Certified Compost – Manufacturer Requirements – Passing Test Results
STA Certified Compost - Test Result Limits for Compost Manufacturers
STA Certified Compost participants must meet the EPA testing limits for heavy metals AND pathogens in every CTDS
(Compost Technical Data Sheet) for every STA Certified Compost product.
METALS - maximum concentrations expressed on a dry weight basis
(Chromium and Molybdenum do not have EPA limits)
Arsenic (As) 41 mg/Kg
Cadmium (Cd) 39 mg/Kg
Copper (Cu) 1500 mg/Kg
Lead (Pb) 300 mg/Kg
Mercury (Hg) 17 mg/Kg
Nickel (Ni) 420 mg/Kg
Selenium (Se) 100 mg/Kg
Zinc (Zn) 2800 mg/Kg
PATHOGENS - pass either Fecal Coliform or Salmonella, at the manufacturers choice.
Must pass both in California.
Fecal Coliform maximum concentrations
< 1000 MPN / gram of dry compost
Salmonella maximum concentrations
< 3 MPN / 4 grams of dry compost